Schizoaffective disorder sits awkwardly between schizophrenia and mood illness
Schizoaffective disorder combines psychosis with bipolar or depressive episodes, and its defining test is timing: psychotic symptoms must persist for at least two weeks with no prominent mood symptoms. Only about 0.3% of people receive the diagnosis, and it is frequently confused with conditions whose treatment and outlook differ.
Clinicians recognise three forms: a bipolar type pairing psychosis with mania, a depressive type, and a mixed type involving both. Hearing voices is the most frequent hallucination, and symptoms usually appear in adolescence or early adulthood, more often in women. Alongside delusions and disordered thinking, many people experience so-called negative symptoms, such as reduced speech, flattened emotional expression and loss of motivation or pleasure, which can outlast and outweigh the more dramatic ones.
The boundaries are fiddly. Under DSM-5, psychosis that appears only during a mood episode points to a mood disorder with psychotic features instead. The criteria were revised because the older DSM-IV rules led to overdiagnosis; estimates under those rules put prevalence at roughly 0.5 to 0.8%, and newer figures are not yet available. Genetic research does not support treating schizophrenia, psychotic mood disorders and this condition as separate diseases with separate causes, suggesting instead a shared inherited vulnerability.
Causes appear to involve genes, disrupted neural circuits and stress, both early in life and current. Researchers have found abnormalities in dopamine, glutamic acid and a compound called tetrahydrobiopterin, and imaging has linked the condition to reduced grey and white matter in several regions and smaller hippocampal volume. Advanced paternal age at conception has been increasingly tied to the wider schizophrenia spectrum. Frequent cannabis use is associated with roughly double the risk of psychosis, although a direct causal role remains debated.
Because psychosis can have physical origins, diagnosis starts by excluding them: blood tests look for thyroid problems, infections such as syphilis or HIV, and metabolic disturbances, and brain scans can rule out lesions. Standard care described in the literature pairs antipsychotic medication with mood stabilisers or antidepressants, plus rehabilitation and psychotherapy, though some researchers worry antidepressants may worsen cycling. A meta-analysis pooling nine small case-control studies found disrupted sleep in patients but no sleep pattern that reliably distinguished them from people with schizophrenia or depression.
Source: Schizoaffective disorder
